Lever operated gripping tool with slidable jaw face



Nov. 22, 1949 E. J. at LAURENCE LEVER OPERATED GRIPFING 'I 'OOL WITH SLIDABLE JAW FACE Filed Sept. 20, 1945 Jim/@2050? 521w; 0/15. M 5

Patented Nov. 22, 1949 LEVER OPERATED GRIPPING TOOL WITH SLIDABLE J AW FACE Ernest J. St. Laurence, Minneapolis, Minn.

Application September 20, 1945, Serial No. 617,646 1 Claim. (01. 81-179) My present invention relates to an improvement in hand-operated gripping tools such as pliers or wrenches of the type incorporating cooperating gripping jaws, one of which has a movable gripping surface mounted for arcuate movements with respect to the cooperating gripping surface of the other jaw. In tools of this type the circumferentially shiftable gripping element of a gripping jaw is provided with segmental bearing surfaces that seat on corresponding segmental seats in the cooperating jaw and the shiftable gripping element is usually retained against accidental displacement by an arcuate slot and pin connection between the gripping jaw element and the cooperating jaw element, one such arrangement being shown in the Seashore Patent 2,285,683 of June 9, 1942.

In tools of the above described type, the retaining pin, referred to, is often accidentally sheared off by stresses placed thereon in service; and this invention is directed particularly to means for preventing this accidental shearing of the retaining pin when stresses applied to the tool tend to move the shiftable jaw element beyond the extreme limit permitted by engagement of one end of the slot with the cooperating retaining pin.

The above and other highly important objects and advantages of the invention will be made apparent from the following specification, claims, and appended drawings.

In the accompanying drawings, like characters indicate like parts throughout the several views.

Referring to the drawings:

Fig. 1 is a longitudinal sectional view through a tool incorporating the invention, with some parts on the sectional line shown in full;

Fig. 2 is an enlarged fragmentary View of the tool shown in Fig. 1, but showing a somewhat different position of the parts;

Fig. 3 is a front end View of the tool of Fig. 1 taken on the line 3-3 of Fig. 1; and

Fig. 4 is a transverse sectional view taken on the line 44 of Fig. 1.

The tool illustrated, and in connection with which a preferred form of the invention is herein illustrated, is of the general character shown in the said Seashore Patent 2,285,683 and comprises a relatively fixed handle element 5, formed integrally with a relatively fixed or rather relatively stationary gripping jaw 5, a cooperating relatively movable gripping jaw I, that is pivotally anchored to the fixed jaw 6 at 8, an operating lever 9 pivoted to the movable jaw l at In, and a toggle link ll pivoted at one end to the lever 9 at l2 and having its other end slid'able in the handle 5. The rear end of the toggle link H works slidably in a slot 13 and the handle 5 is retained against accidental displacement therefrom by a head acting pin 54, and reacts against a screw threaded adjustment screw 15. The toggle link i! at its intermediate portion is provided with a'depending stop lug it that engages the lever 9 when the toggle link H is moved just past dead center in a jaw closing direction. The jaw l is biased to move pivotally in a jaw opening position by means of a coil tension spring IT. The fixed jaw 6 is provided with a fixed gripping element in the nature of a toothed gripping plate 5 that may be assumed to be welded or otherwise rigidly secured thereto.

Preferably and as illustrated herein, the movable jaw element F is formed. of a cooperating pair of sheet metal plates [8 that are riveted or otherwise rigidly secured as at E9. These jaw plates l8 are spread apart beyond their intermediate portions to provide a pair of laterally spaced jaw flanges 20. In accordance with the invention the upper surfaces of these jaw flanges 2B are formed to provide concave seats 2| to receive convex bearing surfaces on shoulders 22 of a shiftable or movable toothed gripping element 23 for the jaw I. The shiftable gripping element 23 is provided, intermediate the convex bearing surfaces 22, with a downwardly projecting guide flange 24 that works between the laterally spaced jaw flanges 20. The movable jaw element 23 is held against accidental displacement from the cooperating jaw l by slot and pin connection comprising a, segmental slot 25 in the guide flange 24 and a cooperating guide pin 26 extending through the spaced jaw flanges 20 and the slot 25.

Circumferential or arcuate movements of the shiftable jaw element 23 are limited in one direction by engagement thereof with the fixed jaw 6, as shown in Fig. 1, or by coincidental engagement of the pin 26 with the outer end of the segmental slot 2 5.

In prior art, tools having sliding jaws of the type described, outward circumferential or arcuate movements of the sliding jaw have been limited solely by engagement of the guide pin with the opposite or inner end of the arcuate slot and tend, under conditions such as shown in Fig. 2, to shear off the guide pin. In Fig 2, the tool is shown as gripping a pipe A between the inner portions of its gripping surfaces, which tends to force the shiftable jaw element 23 beyond the normal limit permitted by engage- 3 ment of the pin 26 with the end of the slot 25 and, of course, this tendency is greatly increased when the tool is turned in a counter-clockwise direction with respect to Fig. 2. In the present tool, however, this tendency is eliminated or greatly reduced by provision on the guide flange 24 of a stop lug or projection 21 with a cooperating stop pin 28 extending through and between the jaw' flanges: 20. The pin 28 is $01 orientated as to* be engaged by the stop lug 21 either just prior to or coincidentally with engagement of the pin 25 with the inner end of slot 25 The pin 28 can be heavier and stronger than is normally used for cooperation in the slot 25.

What I claim is:

In a gripping tool having cooperating jaws mounted for relative movement, one of. said jaws having a relatively fixed gripping surface and the other jaw being provided with an arcuately shiftable gripping element for cooperation with the relatively fixed gripping surfaceof the first named jaw, said second named jaw comprising laterally spaced parallel flanges provided with concave seats, said shiftable grippin element having a plane guide flange projecting therefrom and freely extending into the space between said jaw flanges and said gripping element having convex shoulders on opposite sides ofthe guide flange seated onsaid concaveseats, an arcuate slot and pin connection between the guide flange and the jaw flanges for maintainin said convex shoulders in seatin engagement with said concave seats and for limiting movement of the gripping element in an outward direction, said guide flange being provided with a stop lug projecting therefrom in a direction away from said gripping element, and a stop pin earried-by the jaw flangesand. extending'across the space therebetween, said: pin being disposed beneath said guide flange and in the path of movement of said stop lug for engagement thereby substantially coincidentally with the engagement of the first named pin with an end of its cooperating arcuate slot upon movement of said gripping element in an outward direction, whereby to prevent shearing of the first named pin.

ERNEST J. ST. LAURENCE.

REFERENCES CITED The; following references are of record in the file of this patent:

UNITED STATES PATENTS 

